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1.
利用描述性综述的方法,总结近10年来医疗服务绩效信息透明对医疗质量促进效果,根据纳入排除标准检索Web of Knowledge、Pubmed等数据库,最终纳入31篇密切相关文献。结果表明,国外一般通过医疗报告卡或网站向公众公开医疗服务绩效信息,改善了医疗服务行为,但对病人选择服务提供者和临床结果的改善作用有限。我国应制定相关政策,推动医疗服务绩效信息向更广泛的使用者公开,引导病人利用医疗服务绩效信息选择医疗服务提供者。  相似文献   

2.
Dermatoglyphic investigations conducted by the authors made it possible to demonstrate a genetic predisposition to occupational diseases, in particular, to silicosis and silicotuberculosis. Methods based on the mathematical theory of pattern recognition were used for multifactor analysis of the data. It was shown that complex evaluation of 10 dermatoglyphic indices gave a reliable prognosis of the risk of the above two kinds of disease due to silica dust. The dermatoglyphic patterns which predict predisposition to simple silicosis or to silicotuberculosis were found to differ significantly.  相似文献   

3.
For classifying life forms of plants a proposal was made to use the principle of parallel divergence based on the hypothesis that life forms diverging to any degree preserve further the potential of evolving in a similar way, that is, in parallel series. Life forms of plants are divided into thirteen types corresponding to the nature of their basic metameres. Further, every type is divided into subtypes and sections according to the character of these metameres and then into smaller grades (classification units of the system of living forms corresponding to one trait and its evolutionary level) according to categories of traits: ramification, vegetative flexibility, rate of changes of metameres, types of habitat and environment. On the basis of the principle of parallel divergence scales of traits were constructed for each category. Corresponding to 26 paires of alternative traits 26 degrees of hierarchic classification were devised and within the limits of every type of life form there were 2(26) grades at the lowest rank. Separate systems were developed for single-celled and colonial forms.  相似文献   

4.
A simple case is considered in which the rate of a two-step reaction depends on pH because the intermediate formed in the first step has to gain (or lose) a proton before it can react in the second step, and in which the rate-determining step therefore changes with pH. The curves of reaction rate against pH are shown to be symmetrical, and the sharpest peak possible has a width at half its height of 1.53pH units, i.e. of 2log(3+2 radical2). Any particular curve for this situation proves to be identical with a curve that could be generated for the pH-dependence of a single-step reaction in which the rate is proportional to the concentration of a particular ionic form of a reactant. Curves for the latter situation, however, can have forms impossible for the former case in which the rate-determining step changes, but only if the protonations that activate and deactivate the reactant are co-operative. The peak can then become even sharper, and its width at half its height can fall to 1.14pH units, i.e. to 2log(2+ radical3).  相似文献   

5.
When Escherichia coli strain B/r is exposed to 10 to 20 mug of nitrofurazone per ml, mutants with roughly threefold resistance are obtained. Treatment of these mutants with higher concentrations of nitrofurazone yields strains with six- to seven-fold resistance over strain B/r. Each of these steps toward nitrofurazone resistance is accompanied by loss of soluble nitrofurazone reductase activity. When sensitive bacteria are exposed to labeled nitrofurazone or labeled 2-nitrofuran, a considerable amount of radioactivity becomes bound to the cold trichloroacetic acid-insoluble fraction. Very little activity becomes bound in the mutants with six- to seven-fold resistance; mutants with intermediate resistance show intermediate levels of binding. Partially purified nitrofurazone reductase preparations catalyze the conversion of nitrofurazone to compounds which bind to protein and are not removed by prolonged dialysis against 8 m urea or by cold acid. Nitrofurazone reduced by xanthine oxidase or electrolytically reduced also yields compounds which react with protein to form stable derivatives.  相似文献   

6.
Several recent studies have demonstrated the ability of techniques based on immunoadsorption to selectively isolate specialized subregions of membranes, termed domains, which are derived from a larger more complex parent membrane like the plasma membrane. The immunoadsorbent is directed against a specific antigen that resides exclusively or predominantly in the membrane domain to be isolated. Thus, a monospecific antibody to the domain-specific antigen is required. In the present study we developed a method employing a modified immunoblotting strategy which could utilize polyspecific antibodies to isolate membrane vesicles derived from a specific membrane domain of the hepatocyte plasma membrane. We also used specific cell surface labeling of the hepatocyte plasma membrane by lactoperoxidase-catalyzed iodination at 4 degrees C and preparation of different sized vesicles by sonication to facilitate isolation of the specific domain. For this study, polyspecific antisera were raised in goats against a membrane fraction, denoted N2u, which is enriched in bile canalicular proteins. This antiserum recognizes, among other antigens, a 110,000 Mr polypeptide previously shown to be localized in the bile canaliculus (J. Cook et al. (1983) J. Cell. Biol. 97, 1823-1833). A monospecific antiserum was raised in rabbits against the rat hepatocyte asialoglycoprotein receptor, a sinusoidal domain-specific set of glycoproteins whose major form has a Mr of 43,000. These antisera were each coupled indirectly to different pieces of nitrocellulose by the immunoblotting protocol and were used to isolate membrane vesicles from a crude extract of liver plasma membrane prepared by sonication. The ratio of iodinated asialoglycoprotein receptor to the 110,000 Mr polypeptide in vesicles isolated by the affinity nitrocellulose immunoadsorbent method indicate a 10- to 15-fold enrichment of sinusoidal-derived vesicles relative to bile canalicular-derived membrane vesicles. These results show that the affinity nitrocellulose immunoadsorbent method can be used to isolate domain-specific vesicles. Further, the affinity immunoadsorbent method described here for the isolation of domains of the plasma membrane is an integrative one allowing isolation of vesicles present in relatively small concentration in crude cell extracts and it requires minimal ultracentrifugation time.  相似文献   

7.
[目的]研究4种品系小鼠的寒、热体质。[方法]8~9周龄昆明、BALB/c、C57BL/6J、ICR小鼠,以及4~5周龄昆明小鼠,同步系统检测其生物学特性,然后以统一的评价标准评价4种品系小鼠的寒、热体质。并对BALB/c小鼠给予参桂理中丸和利血平做药物反证。[结果]①4~5周龄昆明小鼠与8~9周龄昆明小鼠比较体质明显偏热;②BALB/c小鼠与C57BL/6J小鼠比较体质偏寒;③8~9周龄雄性BALB/c小鼠、雄性和雌性C57BL/6J小鼠与8~9周龄相应性别昆明小鼠比较体质无明显差异;8~9周龄雌性BALB/c小鼠与8~9周龄雌性昆明小鼠比较体质偏寒;④8~9周龄ICR小鼠与8~9周龄BALB/c小鼠、C57BL/6J小鼠比较体质偏热;8~9周龄雄性ICR小鼠与8~9周龄雄性昆明小鼠比较体质偏热。[结论]4种品系小鼠存在寒、热体质差异。  相似文献   

8.
The antibiotic resistance and lipid composition of rhodococci grown in rich organic media with gaseous or liquid n-alkanes were studied. Hydrocarbon-grown rhodococci exhibited an increased resistance to a wide range of antibiotics (aminoglycosides, linkosamides, macrolides, beta-lactams, and aromatic compounds). The enhanced antibiotic resistance of rhodococci grown on n-alkanes correlated with an increased content of total cell lipids (up to 14-28%) and saturated straight-chain fatty acids (C16:0, C18:0, C21:0) and was accompanied by the appearance of cardiolipin and phosphatidylglycerol in cells. These lipid compounds were supposed to promote the formation of nonspecific antibiotic resistance in rhodococci by decreasing the permeability of their cell envelope to antibiotics.  相似文献   

9.
The extraordinary ability of the bacteriophage Qβ replicase to amplify RNA outside the cell attracted the attention of molecular biologists in the late 1960s-early 1970s. However, at that time, a number of puzzling properties of the enzyme was not explained. Not until recently has Qβ replicase begun to reveal its secrets, promising to give a key not only to understanding the mechanism of replication of the bacterial virus genome but also to the solution of more general fundamental and applied problems.  相似文献   

10.
Glycine injection to the identified area of the RVLM leads to the development of a characteristic depressor reaction, due to a decrease of the total peripheral vascular resistance (TRP). Glycine injection to the identified area of CVLM results in the developing pressor reaction also due to the changes of TRP. Glycine injection to CVLM under preliminary functional switch-off the RVLM neuronal activity is not accompanied by the development of pressor reaction. This can be an evidence that CVLM sympathoinhibitory neurones act on cardiohemodynamics by their interaction with RVLM sympathoexcitatory neurones. Turn off of the tonically active sympathoinhibitory CVLM neurones does not affect the character of the reactions depending on the inhibition or excitation of sympathoexcitatory RVLM neurones.  相似文献   

11.
At equilibrium, water addition to the 5,6 double bond of NADH was observed to favor the hydrate by a factor of approximately 100. Hydration generates two epimers of NADHX (beta-6-hydroxy-1,4,5,6-tetrahydronicotinamide adenine dinucleotide). Only the 6S epimer of the hydrate was found to serve as a true substrate for an ATP-dependent dehydratase from yeast that regenerates NADH. Yet enzymatic conversion of both epimers of the hydrate to NADH was found to proceed essentially to completion in the presence of ATP and dehydratase. This is explained by the observed ability of the epimers to undergo rapid spontaneous equilibration, so that it is unnecessary to postulate a lack of stereospecificity in the dehydratase.  相似文献   

12.
Mechanisms of toxicity continue to be important in developing rational strategies to deal with chemicals present in the environment. Understanding and predicting toxicity have also become a critical step in the process of drug development. Covalent binding of chemicals to macromolecules is one aspect of toxicity, and the principles and outcomes of the process are considered. Two examples of chemicals for which several aspects of metabolism and reactions are understood are aflatoxin B(1) and polyhalogenated olefins. Ethylene dibromide is a compound that is activated to genotoxic half-mustards by conjugation with glutathione or the DNA repair protein O(6)-alkylguanine DNA alkyltransferase (AGT). The AGT reaction is unusual, in that crosslinking of the protein to DNA increases mutagenicity. One of the involved mechanisms is formation of N(7)-guanyl crosslinks and depurination to produce G-->T transversions; other reactions appear to yield the additional mutagenic events. The phenomenon of thiol conjugation to increase mutagenicity is widespread among bis-electrophiles.  相似文献   

13.
The involvement of the carbohydrate components of the Azospirillum brasilense Sp245 capsules in bacterial protection from the action of extreme factors was investigated. The survival of encapsulated and non-encapsulated azospirilla exposed to elevated (46-48 degrees C) and below-freezing (-20 and -70 degrees C) temperatures, extreme pH values (2 and 10), and to drying was studied. High-molecular-weight carbohydrate-containing complexes (lipopolysaccharide-protein complex and polysaccharide-lipid complex) were isolated from the capsular material of azospirilla. It was shown that the addition of these complexes to the suspension of decapsulated cells before exposing them to extreme factors enhanced their survival rates by 15 to 51%.  相似文献   

14.
Urine of a fucosidosis patient contained a large amount of fucosyl oligosaccharides and fucose-rich glycopeptides. Six major oligosaccharides were purified by a combination of Bio-Gel P-2 and P-4 column chromatographies and paper chromatography. Structural studies by sequential exoglycosidase digestion and by methylation analysis revealed that their structures were as follows: Fucalpha1 leads to 6GlcNAc, Fucalpha1 leads to 2Galbeta1 leads to 4(Fucalpha1 leads to 3)GlcNAcbeta1 leads to 2Manalpha1 leads to 3Manbeta1 leads to 4GlcNAc, Galbeta1 leads to 4(Fucalpha1 leads to 3)GlcNAcbeta1 leads to 4Manalpha1 leads to 4GlcNAc, Galbeta1 leads to 4(Fucalpha1 leads to3)GlcNAcbeta1 leads to 2Manalpha1 leads to 6Manbeta1 leads to 4GlcNAc, and Galbeta1 leads to 4(Fucalpha1 leads to 3)GlcNAcbeta1 leads to 4Manalpha1 leads to 6Manalpha1 leads to 6Manbeta1 leads to 4GlcNAc. In additon, the structure of a minor decasaccharide was found to be Galbeta1 leads to (Fucalpha1 leads to)GlcNAcbeta1 leads to Manalpha1 leads to [Galbeta1 leads to (Fucalpha1 leads to)GlcNAcbeta1 leads to Manalpha1 leads to]Manbeta1 leads to 4GlcNAc.  相似文献   

15.
16.
The inhibitory effect of xenobiotics known to damage cell surface structures was studied. The sensitivity of suspended cells of the two fungi Candida maltosa and Fusarium proliferatum was compared with that of artificial or natural biofilms of these fungi. The results obtained indicate that the resistance of attached cell populations to model xenobiotics is increased compared with suspended cells. Only the attached fungal cells had the capacity to degrade acetone and phenol and to adapt to increasing concentrations of these substances, so they seem ideally suited for bioremediation of waste water.  相似文献   

17.
To investigate potential complementary activities of multiple enzymes belonging to the same family within a single microorganism, we chose a set of Old Yellow Enzyme (OYE) homologs of Pseudomonas putida. The physiological function of these enzymes is not well established; however, an activity associated with OYE family members from different microorganisms is their ability to reduce nitroaromatic compounds. Using an in silico approach, we identified six OYE homologs in P. putida KT2440. Each gene was subcloned into an expression vector, and each corresponding gene product was purified to homogeneity prior to in vitro analysis for its catalytic activity against 2,4,6-trinitrotoluene (TNT). One of the enzymes, called XenD, lacked in vitro activity, whereas the other five enzymes demonstrated type I hydride transferase activity and reduced the nitro groups of TNT to hydroxylaminodinitrotoluene derivatives. XenB has the additional ability to reduce the aromatic ring of TNT to produce Meisenheimer complexes, defined as type II hydride transferase activity. The condensations of the primary products of type I and type II hydride transferases react with each other to yield diarylamines and nitrite; the latter can be further reduced to ammonium and serves as a nitrogen source for microorganisms in vivo.  相似文献   

18.
The degree of deacetylation (DDA) of chitosan determines the biopolymer's physico-chemical properties and technological applications. pH-Potentiometric titration seems to offer a simple and convenient means of determining DDA. However, to obtain accurate pH-potentiometric DDA values, several factors have to be taken into consideration. We found that the moisture content of the air-dry chitosan samples can be as high as 15%, and a reasonable fraction of this humidity cannot be removed by ordinary drying. Corrections have to be made for the ash content, as in some samples it can be as high as 1% by weight. The method of equivalence point determination was also found to cause systematic variations in the results and in some samples extra acid as high as 1 mol% of the free amino content was also identified. To compensate for the latter effect, the second equivalence point of the titration has to be determined separately and the analytical concentration of the acid be corrected for it. All the corrections listed here are necessary to obtain DDA values that are in reasonable agreement with those obtained from (1)H NMR and IR spectroscopic measurements. The need for these corrections severely limits the usefulness of pH-metry for determining accurate DDA values and thus potentiometry is hardly able to compete with other standard spectroscopic procedures, that is, (1)H NMR spectroscopy.  相似文献   

19.
Methods are given for determining the degree of separation of a large number of overlapping multiple, similar Gaussian peaks in terms of their standard deviations. One approach is to relate the degree of separation to the ratio of the difference between the peak and valley heights to the height above the baseline. Another method relates the degree of separation to the ratio of the peak width to the valley width, and is independent of the location of the baseline. It is noted that when a large number of similar peaks is present there does not appear to be any definite minimum degree of separation necessary in order to obtain discernible resolution; separations less than two standard deviations produce visible, separate peak tops.  相似文献   

20.
Mechanism of methylmercury cytotoxicity was investigated with special reference to its preferential action on microtubules and protein biosynthesis in cultured cells. The tubulin synthesis analyzed by autoradiography of two-dimensional electropherogram using35S-methionine was inhibited by 50–70% in mouse glioma cells exposed to 5×10?6 M methylmercury for 3 h, which almost completely depolymerized microtubules. Total protein synthesis monitored by incorporation of labeled methionine into acid insoluble fraction was decreased slightly but significantly and the protein bands other than tubulin on gradient urea-PAGE gel appeared to remain unchanged under the experimental condition used. These results suggest that the inhibition of protein synthesis observed on exposure to methylmercury can be ascribed, at least partly, to a possible autoregulatory depression in tubulin synthesis owing to the increase in the pool of tubulin subunits resulted from microtubule depolymerization by methylmercury.  相似文献   

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